SAAMI specs for 260 rem versus 6.5 Creedmore seem to indicate that the 6.5 Creedmore chamber is ever so slightly smaller than the 260 rem and therefore (in ignorant newbie logic) it could be rechambered to the ever so slightly larger 260 rem?
Thousandths Matter!

IMO watching how barrels are made, it would be impossible. Also, company wise, it would be a liability issue as well.

It would be less expensive to buy a new pre-fit barrel.

In the interest of safety, I would forget the idea.

Dennis